Aliens Are Not Crazy Unlikely

Astrobiologists have, for decades, defaulted to a conservative burden of proof that leans into two aphorisms coined by Sagan … life … should be considered a “hypothesis of last resort,” largely because “extraordinary claims require extraordinary evidence.” But what if Sagan had it all wrong? If we live in a universe where life is common and not extraordinary at all, setting such an extraordinarily high bar for its discovery beyond Earth can backfire. … “There’s all these different lines of evidence that keep coming together that make me go, ‘Gosh, it’s becoming more and more difficult to explain everything on Mars abiotically’” … The most compelling clue comes via a reddish mudstone found by Perseverance that’s dappled with “leopard spots,” or mineral assemblages that contain chemically altered iron and organics. (More)In ’61, Claus & Nagy presented in Nature signs of life in Orgueil and Ivuna meteorites. Science published rebuttals to one sign; dispute still open. In ’76, the Viking…